Planets

Planets are lumps of gas and rock held close to a star by the force of
gravity. We live on planet Earth going round star Sun, along with severn other planets and thousands of smaller objects.
Together these are called the Solar System.

Although they are all difficult to see, hundreds of planets have been
discovered near Sun-like stars. Looking for planets near a star is a bit like
trying to watch a moth flying around a spotlight which is pointing at you --
you get dazzled by the light.

Since discs of gas and dust have been
detected around some young stars, we guess that planets might be common. But
none of the planets so far discovered are like our Solar System. Indeed these
discoveries are challenging current theories of the origin of planets.

If planets like ours are common, then life too could be common in the Galaxy.

Artist's impression of star birth
copyright Joe Tucciarone

Here we give a brief overview of planets
orbiting the Sun. In the Reference Section we
describe them in a little more detail.

Recent discoveries of planetary systems
outside our own are challenging current ideas on how the Sun and its eight planets, the solar
system, originally formed. The story which follows, therefore, may soon be
changed in the light of new discoveries.